He tried to find doctors who could save his wife, but the disease advanced too quickly. "The cancer got in her lymph nodes, and finally, she died," he says. "With that I said, 'What I want to do is find a cure for cancer.' I wanted to solve it, because I was very much in love."
David opened the North Carolina Research Center, one of the country's premiere life extension research labs, and changed the way he lived his life.
During a visit to David's home, Oprah sees how a diet of natural foods and commitment to exercise can change our definition of "old age."